1. Field of the Invention
The present invention generally relates to a semiconductor device and a method of manufacturing the semiconductor device, and more particularly, to a semiconductor device that has a semiconductor layer subjected to etching, with a Ni film serving as a mask, and a method of manufacturing the semiconductor device.
2. Description of the Related Art
When dry etching is performed selectively on a substrate or a semiconductor layer, the etching is performed on the substrate or the layer to be subjected to etching, with a mask layer serving as a mask. The mask layer is formed selectively on the substrate or the layer to be subjected to etching. If the reaction constant of the substrate or the layer to be subjected to etching is small, the speed at which the etching is performed on the substrate or the layer to be subjected to etching is low. Particularly, in a case where etching is performed on a thick substrate or a thick layer, the etching selectivity that represents the etching speed ratio of the mask layer to the substrate or the layer to be subjected to etching is required to be high, so that the mask layer cannot be lost during the etching. For example, Japanese Patent Application Publication No. 2003-224300 discloses a technique of performing etching on a GaN (gallium nitride) film, with a mask being a mask layer consisting of a silicon oxide film and an aluminum oxide film.
The mask layer used for etching needs to have high etching selectivity with respect to the material to be subjected to etching. Further, detachment of the mask layer due to a temperature change during the etching must be prevented.